Along with the development of vehicles, not only mechanical devices which used to be the core elements that make up a vehicle, such as an engine, a shaft, and a wheel, but also in-vehicle electronic devices that fine-control the mechanical devices, using an IT technology have been increasingly important. In addition, the number and the complexity of electrical and electronic equipment applied to a vehicle are also increasing.
In the automotive field, a head unit, particularly, has been recognized as one of the most important devices. A head unit is usually located in the middle of the front seat of a vehicle. A head unit is a synthesis control device in which a temperature control device such as an in-vehicle air conditioner and a heater, an entertainment system, a rear-view camera display, a GPS system, etc., are integrated.
There is a case where a button capable of controlling the head unit is attached to a user steering wheel for a safety reason, and such a button may also be included in the category of the head unit in a broader sense. A user controls various in-vehicle devices through a head unit before starting driving, during the driving, and at the time of finishing driving.